Animal Instincts
by Nyxelestia
Summary: Missing scenes and POVs from Fullmetal Alchemist: Brotherhood. Five times Edward Elric was nothing but a reluctant, belligerent ally to the chimeras - and one time Heinkel could admit he was a little more than that. 5 plus 1 "found family feels" fic of the Chimera Dads being Dads to a teenager with Amestris' weirdest daddy issues. Minor gore, medium angst, major hurt/comfort.
1. Chapter 1

_First published to AO3 on Jan. 1, 2019._

 _ _Written for Fullmetal Secret Santa 2018._ Happy Holidays to Tumblr user satoshigekk0uga!_

* * *

It could've been a moment since Kimblee destroyed the mineshaft, or it could've been a day; Kurt Heinkel would not have been able to tell anyone as he swam in and out of consciousness, let alone figure out how he was going to get himself out of this mess.

As he regained his grasp of the waking world, he heard a small and angry voice from a few feet away:

 _"I won't make her cry…especially not over something this_ stupid _!"_

Stone columns erupted from the ground and lifted all the rubble off of him and Darius. He gasped in a deep breath as his chest was freed, and rolled onto all fours the moment he was no longer pinned.

"Damn…" he grumbled as they crawled out. "Kimblee's gonna _pay_!"

Because Kimblee had blown up this mineshaft with them still inside of it - and left them for dead. Meanwhile…

"Hey, Fullmetal kid, you still alive?" Darius called out.

Halfway across the mineshaft, the Fullmetal Alchemist lay bleeding and broken before them. Heinkel's gut clenched in sympathy when he realized where all that blood was coming from.

If it weren't for the fire in those golden eyes peeking out from sweat-soaked hair, and the labored movement of his chest, Heinkel would've assumed the kid was dead already.

How _was_ he still alive?

"What made you decide to rescue us?" Darius continued.

"Don't get the wrong idea…" A painful inhale and exhale. "I can't pull this…out of my stomach…on my own." Another labored breath. "I could use…a bit of help."

Heinkel's entire sympathetic midsection throbbed as he and Darius looked at each other in wary consideration.

Fullmetal was their enemy, and they'd been trying to kill him…

…for Kimblee - who'd left them for dead after nearly killing them, himself.

Soldiers died in war, and Heinkel didn't expect his superiors to prioritize his life or rescue him…but to actively throw their lives away?

And not even get their enemy in the process?

"Well," Darius finally answered for them, as they lumbered over to the kid. "It's not like we were given orders to _kill_ you."

Fullmetal had been a goddamned menace when jumping around all over the place and transmuting insane alchemy. It was only when the kid was still and half-dead like this that Heinkel realized how tiny he was.

So small, so young, and still so dangerous.

Darius lifted the boy into his lap. Compared to the man's gorilla-form bulk, the kid almost looked like a doll.

An angry, whimpering doll, who'd already lost too much blood.

And the beam wasn't even out of his gut yet.

"You know kid," he said, wrapping his clawed hands around the front end of it anyway. "You're gonna bleed to death pretty quickly once I pull this out."

Whether the kid died of blood loss five minutes from now or _right_ now, what difference did it make? Fullmetal saved his life, the least Heinkel could do was let the kid die on his own terms.

Except-

"Not if I heal it first," the kid gasped out. Even speaking must be painful at this point - Heinkel could feel the vibration of the words through the metal beam in his paws. "As soon as its out of me, I'll close up the wound with alchemy."

Heinkel wished he could have the kind of faith in _anything_ that this kid had himself. But upon learning the kid had never done more than a little research into medical alchemy - and was somehow shortening his own life force to heal himself? - Heinkel was sure he was just granting the kid a less undignified death by doing this.

He sighed as the kid ground out something about the cost of mercy. If a decent death was all he could do, then it's what he _would_ do.

Bracing himself and tightening his grip on the beam, he asked the kid, "Ready?"

Fullmetal closed his eyes, taking a deep and painful-sounding breath, and held up his hands like he was about to applaud Heinkel painfully killing him - his automail arm still transmuted into a blade.

"Yeah," the kid croaked out. "I'm ready."

He really was.

 _Heinkel_ almost wasn't.

As soon as the beam started moving, Fullmetal grunted in pain, eyes wide and teeth clenched so hard Heinkel was half convinced he'd break them. With his enhanced animal hearing, he could hear the sounds of enamel grinding on enamel.

That, and the wet, squishy, tearing sound of his internal organs being torn apart by the moving metal beam.

And the _smell_. Blood, stomach acid, and other bodily fluids he could not and did not want to name-

The screaming didn't start until a moment later.

Darius looked as terrified as Heinkel felt, holding down the screaming kid, thrashing in his lap in agony. Heinkel did his best not to jostle the beam and the kid too much as he leaned forward, moving a knee onto the kid's automail thigh to minimize his writhing movement. He still winced at the blood splattering over his own trousers and soaking into the rough fabric remains over his other knee.

Holding down and torturing a kid was not what Heinkel had signed up in the military for, or even signed up in the Amestrian Enhancement Program for.

The screaming echoed around the mine shaft, wrapping all around and smothering them.

The only reason Heinkel didn't let go and keel over at what he was doing, was the knowledge that doing so would lead to an even more painful death for the kid.

No matter what kind of threat Fullmetal had posed to their country, stupid kids like him shouldn't be dying so painfully.

As soon as the beam cleared his skin, with a squelch that Heinkel wished he couldn't hear over the screaming, Fullmetal clapped and pressed his hands against the edge of the giant hold in his side.

For a brief moment, Heinkel could see the gray-pink tissue of the kid's internal organs through his fingers.

Then blue lighting flashed around Fullmetal, so bright Heinkel couldn't even look at the wound. Frozen as he was, he tried to glance up at Darius, but the man only had eyes on the kid's face.

The screaming and the lightning faded in tandem, and the kid's eyelids fell in time with the beam that dropped as Heinkel slumped.

He wasn't exactly relieved, so much as relieved it was over.

Or at least he hoped it was.

Thankfully, most of the clothing was still intact; all the healing alchemy in the world wouldn't help him if he froze to death in the Northern cold. But what little Heinkel could see of his stomach looked like one giant scab, and most of the fabric around it was soaked in blood.

"Did he make it?" he asked.

Before Darius could answer, the kid huffed. The movement made his cowlick _bounce_ up, as he cracked open one eye.

His gaze still held fire at its core, even through the pain.

Heinkel finally let go of the beam, not even flinching at the clatter - not after all that screaming.

"You can't kill me-" Was that twist of his mouth a _smile_?! "-that easily."

Twisted mouth or twisted kid, Heinkel didn't know which it was, nor which he preferred.

Not that it mattered much, since their troubles weren't all over, yet. The kid's work was a patch job at best, and he needed to see a doctor-

"N-no," Fullmetal protested, pushing their hands away with all the strength of a newborn cub. "I don't have time…for that…"

The Fullmetal Alchemist staggered upright, clutching his midsection and swaying on his feet. He didn't seem to notice either all the blood trickling down his little body and into the pool on the floor, nor the incredulous men beside him.

"I've gotta stop Kimblee," He muttered while…while _walking_ , taking a staggering step forward, and another, dripping blood from where his hand was still clamped around his gut. "Before he gets…" Another shaking step. "…to…"

Predictably, the kid collapsed back onto the ground.

" _Idiot!_ " Heinkel muttered.

"There's no way you could fight Kimblee in your condition," Darius grumbled, approaching the unresponsive kid.

Heinkel shook his head, standing up as his mane ruffled and settled around him. His leonine joints cracked in protest as he stood, but his motion was smooth despite the little jolt of stiffness.

The movement of his mane settling out of the corner of his eye made something ruby red sparkle in the vestiges of the sunlight…

It should probably take more than two minutes to throw away his career, but between the chimera business and Kimblee himself…

Heikel didn't know if it was the human in him that wanted to cheer, or the lion in him that wanted to roar. Either way, pocketing Kimblee's Philosopher's Stone felt like a victory he needed to celebrate as loud as possible.

The only reason he didn't was the small body that Darius helped load onto Heinkel's back with his one, good arm.

"The kid saved our life," Darius said. With the way the gorilla chimera adjusted the unconscious kid, pressing him a little more securely to the lion's back, Heinkel doubted it was just the life debt he was thinking of. "We need to get him to a real doctor."

The lion chimera could barely feel the bumping of Fullmetal's head against the back of his shoulder as they walked toward the only safe exit left. He knew the kid's size was far from what made him dangerous, and he knew his own body's strength was augmented with the lion mixed into him now. He'd seen the damage the kid could do despite missing half his limbs, had just witnessed the kid perform revolutionary alchemy on himself while bleeding to death, and had seen all sorts of tactical reports on how dangerous the State Alchemist he was carrying could be.

Despite having known all that for weeks, Heinkel had to _remind_ himself that he was carrying a dangerous alchemist as he followed Darius. The weight in his hands and on his back was negligible. This kid was too young to be bleeding to death in the bottom of a mine shaft, to be facing off against psychopaths like Kimblee, or to be fighting for the military.

Two chimeras and half an alchemist didn't make for much of a pride. But when Darius and Heinkel both winced at the pained, unconscious whimper in the bite of Briggs' breeze, Heinkel got a sinking feeling they were on the path to making one with this idiotic yet extraordinary cub they now had in their hands.

If they could keep him alive for long enough.


	2. Chapter 2

North City was almost a day's walk away, and night was already falling.

"He's more likely to last if we keep him stable and warm…" Heinkel shifted his hands under Fullmetal's limp legs to keep the kid secured to his back. "…than trying to move through the cold night."

By now, the last few Briggs soldiers had gone back to their base, and they'd left in a hurry. There wasn't much left in the abandoned office Kimblee had been planning in, earlier that day. But the building was well insulated, and a bit off the main room was a former storage space. It was small and easy to warm with a little fire, no windows to cover to keep the light and heat in, only one entrance to guard. Best of all, the hallway leading to it was long and echoing — easy to hear if attackers were approaching.

"We need to stay in these forms," Heinkel continued, even as he grimaced at the thought of trying to _sleep_ in his lion form. "We don't have much food."

The meager military rations they had found left behind were barely enough for humans, so definitely not enough for chimeras — and the more they changed between shapes, the more food they needed.

That wasn't the only reason they needed to stay shifted, though.

Darius took the first watch, so Heinkel lay Fullmetal out on the ground, keeping his wounded side toward their little fire. Then, as awkward as he felt about it, he curled around Elric's other side, his lion fur warming his own body as well as blanketing the kid's.

Without much kindling they could safely burn in such an enclosed space, they needed to use body heat to make sure Fullmetal survived the cold night.

Even through the fur, Heinkel flinched a little as he came in contact with the cold alloy of the kid's automail arm. It took a few moments to warm up, even with the fire, which was more than enough time for Darius to realize what Heinkel's hiss of discomfort was about.

"How the hell does a teenager lose not just one, but _two_ , limbs?" Darius murmured, eyes tracing over the glimpses of metal through Elric's torn pant leg.

"Honestly? I can think of plenty of ways people, especially soldiers, lose limbs," Heinkel answered, keeping his voice as low as possible. Not that he expected it to matter — the kid was out cold, colder than the snowy night outside. "And all this kid needs is particularly bad luck, for that to happen to him twice. But how the hell did he become a State Alchemist so young?"

"The People's Alchemist," Darius quoted, the flickering firelight haunting his simian features with shadows. "Heard so much about him over the years. Everything I read in the newspapers, everything he did, everything people say about him, it just seems so… _big_." A particularly ape-like huff followed a human's nervous swallow.

Heinkel hummed in agreement, looking back down at the kid. "Too big."

The kid laid out by his belly seemed far too small to be the most acclaimed alchemist in Amestris, to be the hero of the people, to be a major in their military.

"Hard to believe he outranks us," he continued.

Darius snorted, a half-laugh darkened not by his primate vocal chords, but by worried disbelief.

Kids had no business being in the military and outranking monsters like them — not even child prodigies, no matter how combat proficient they were.

Though that just begged another question:

"Where the hell did this kid learn to fight?"

As Heinkel's latest question hung over the waning fire, Darius shrugged.

The gorilla chimera kept his gaze focused on the flames warming his hands and feet, even as he kept one ear cocked towards the doorway. "Maybe it's related to how he lost his limbs?"

Thinking of only a few ways those could be related, Heinkel shuddered at the thought.

"None of this explains _why_ he became a State Alchemist, either," Darius continued. At Heinkel's visible confusion, he elaborated, "Kid fought hard, and was willing to hurt us bad, but he was trying _not_ to kill us. Who the hell joins the military when they refuse to kill people?"

"That…is actually a very good question. " Heinkel tried to think of an explanation, but each one he could come up with was worse than the last. "But a very disturbing one, too."

Darius sighed, the sound coming long and loud from his half-gorilla lungs.

"Well, we'll need to keep him alive if we want answers," Darius said. "And we can't do that if we're too exhausted to get him to a doctor. I'll take the first watch, and we'll go in shifts of-"

"How're you gonna know when to wake me up for the second one?" Heinkel asked.

Darius looked speculatively at the kid. "State Alchemist, right? He'll have a pocket watch on him."

Heinkel started to reach over to rifle through the kid's pockets, but then realized with his paws, he might actually wake the kid up. Darius must've realized this, too, waving off Heinkel as he stepped around the little fire and used his much more primate fingers to find and extract the silver watch. The state dragon engraved on its front gleamed in the firelight, as if it were a spark away from coming alive.

Such a powerful symbol had no right looking so tiny in his hand.

The clasp was stuck, so Heinkel ended up needing to reach out and help. It took two tries with his claws to pop it open, and once he did-

"Is that an engraving?" Darius asked, squinting at the inside of the cover of the watch. He tilted it away from Heinkel, towards the firelight. "Don't Forget," he read aloud. "October 3rd, 1910."

"Wonder what happened?" Heinkel muttered.

"Well, I'll wake you up in…three hours?" Darius said. Heinkel nodded, the tips of his mane brushing over the kid's unresponsive face. "Three hours," he confirmed. "So get some sleep."

As Darius hunkered down on the other side of the fire, Heinkel curled up a little tighter around the kid, fighting the strong urge to wrap an arm around him like he was a particularly violent teddy bear.

You better live the night, kid, Heinkel thought, closing his eyes as exhaustion started to seep in. I have so many questions for you.

Not that he really cared that much for answers — just that the kid be well enough to tell them.


End file.
